晶体生长时的固液相结构变化分析

晶体的溶解、熔化以及结晶成核生长时的固液相原子结构是怎样变化的,晶体生长时的生长基元是原子还是原子团.本文根据各种材料液相结构的最新研究结果,提出不饱和配位结构转换模式,并以此模式对各种常见晶体材料从溶解、熔化到结晶生长时的液态母相结构变化以及晶体成核过程进行了描述和分析,认为晶体生长时的界面结构和液相结构十分接近,溶解、熔化主要是晶体表面的不饱和配位原子(离子)转换到液相结构的过程,晶体生长主要是液相中的不饱和配位原子(离子)转换到固液生长界面的位错位置,使配位结构更饱和的过程.随着液相过饱和度的增大,液相结构单元的原子数越来越多,吸附到晶体生长界面若来不及转换回液相,就形成新的位错生长中心,形成晶体生长缺陷.

Analysis on the Structure Transformation during Crystal Growth from Liquid

How does the atom structure transform when the crystal is melting, nucleating and growing from the liquid? What is the growth unit ? Atom or atomic group? The model of unsaturated coordination transition was configured to describe the structure transformation during crystal growth from the liquid. It is supposed that the structure of crystal growing interface is similar to that of liquid. The unsaturated coordination atoms of crystal's surface transit into the liquid primarily when the crystal is melting. The unsaturated coordination atoms transit into the dislocations of the crystal's face from the liquid and become approximately saturated coordination when the crystal is growing. The number of atoms in liquid structure units will increase when liquid supersaturation is increased. The big structure unit will become a new dislocation center when it is adsorbed on the crystal surface and can not transit into the liquid immediately,resulting in crystal defects.